E2-644

UbcH8 can be charged with both ubiquitin and ISG15 via the activities of the respective UBA1 and UBA7 enzymes. UbcH8 is highly homologous to UbcH7, and functions in ubiquitin conjugation reactions and in HECT E3 (such as E6-AP) and RING-FINGER (such as Parkin) protein mediated events. UbcH8 is the major E2 for ISG15 conjugation in reactions initiated by the ISG15-specific E1 activating enzyme. ISG15 is an ubiquitin-like protein that is conjugated to cellular proteins after IFN-α/β stimulation.